This invention relates to improvements in circular knitting machines, and more particularly to multi-feed knitting machines comprising a rotary cylinder having a plurality of vertical slots in which needles provided with hooked upper ends are housed. The machines according to the invention introduce one or more independent wrap yarns to selected needles to form walewise effects in a fabric of jersey construction. The wrap yarn so introduced may be received by a single needle selectively raised to a yarn receiving position, to form a walewise pin stripe effect in the fabric; or the wrap yarn may be introduced to one or more needles to form single needle and/or multi-needle wrap effects in one or more courses of the fabric.